More than a quarter of children grow up in families where one or both parents have a psychological issue, drug or alcohol addiction, according to the Trimbos Instituut.

The addiction and mental health institute believes that more children are growing up in this situation and, as a result, have a higher chance of developing psychological problems as adults.

Around 671,000 parents are believed to have an addiction or mental health issue, and around 900,000 children under the age of 18 are thought to be growing up in an affected family. This means, estimates Trimbos, that 27.9% of children living at home have at least one parent with these issues – almost double the level of previous estimates.

The new figures are based on a long-running study on the psychological health of Dutch adults, the NEMESIS.

Project leader and researcher Anouk de Gee said that the numbers are probably an underestimate. “We are concerned,” she said. “It is important that these children and also their parents get the right support. We know that with preventative help, the chance that these children develop problems later will be a lot lower.

“There is help available but the biggest problem is reaching these parents and children.”